In this May 3, 2012 photo provided by CBS, Stephen Colbert, left, host of the “Colbert Report” on the Comedy Central Network, has a laugh on stage with host David Letterman on the set of the “Late Show with David Letterman,” in New York. Colbert says on a visit to the late-night show he’ll take over next year he’s obviously “thrilled” to be succeeding David Letterman. The Comedy Central host told Letterman on CBS’ “Late Show” on Tuesday, April 22, 2014, he’s going to do whatever Letterman has done. (AP Photo/CBS, John Paul Filo) MANDATORY CREDIT, NO SALES, NO ARCHIVE, FOR NORTH AMERICAN USE ONLY

In this May 3, 2012 photo provided by CBS, Stephen Colbert, left, host of the “Colbert Report” on the Comedy Central Network, has a laugh on stage with host David Letterman on the set of the “Late Show with David Letterman,” in New York. CBS announced on Thursday, April 10, 2014 that Colbert will replace Letterman as “Late Show” host after Letterman retires in 2015. (AP Photo/CBS, John Paul Filo) MANDATORY CREDIT, NO SALES, NO ARCHIVE, FOR NORTH AMERICAN USE ONLY

In this May 3, 2012 photo provided by CBS, Stephen Colbert, left, host of the “Colbert Report” on the Comedy Central Network, joins host David Letterman on the set of the “Late Show with David Letterman,” in New York. CBS announced on Thursday, April 10, 2014 that Colbert will replace Letterman as “Late Show” host after Letterman retires in 2015. (AP Photo/CBS, John Paul Filo) MANDATORY CREDIT, NO SALES, NO ARCHIVE, FOR NORTH AMERICAN USE ONLY

In this May 3, 2012 photo provided by CBS, Stephen Colbert, left, host of the “Colbert Report” on the Comedy Central Network, joins host David Letterman on the set of the “Late Show with David Letterman,” in New York. CBS announced on Thursday, April 10, 2014 that Colbert will replace Letterman as “Late Show” host after Letterman retires in 2015. (AP Photo/CBS, John Paul Filo) MANDATORY CREDIT, NO SALES, NO ARCHIVE, FOR NORTH AMERICAN USE ONLY

FILE - In this Oct. 13, 2013 file photo, Stephen Colbert delivers the keynote address during the Alfred E. Smith Memorial Foundation Dinner, a charity gala organized by the Archdiocese of New York, at the Waldorf-Astoria hotel in New York. Comedy Central deleted a message Thursday, March 27, 2014, from its "Colbert Report" Twitter feed showing a still from Wednesday night's show where Stephen Colbert joked about starting a "Ching-Chong Ding-Dong Foundation for Sensitivity to Orientals or Whatever." The joke was part of a skit in which Colbert talked about the Washington Redskins' owner buying things for Native Americans upset with the team's name.(AP Photo/Jason DeCrow, file)

FILE - In this Oct. 13, 2013 file photo, Stephen Colbert delivers the keynote address during the Alfred E. Smith Memorial Foundation Dinner, a charity gala organized by the Archdiocese of New York, at the Waldorf-Astoria hotel in New York. Comedy Central deleted a message Thursday, March 27, 2014, from its "Colbert Report" Twitter feed showing a still from Wednesday night's show where Stephen Colbert joked about starting a "Ching-Chong Ding-Dong Foundation for Sensitivity to Orientals or Whatever." The joke was part of a skit in which Colbert talked about the Washington Redskins' owner buying things for Native Americans upset with the team's name.(AP Photo/Jason DeCrow, file)

Stephen Colbert is introduced as he takes the dais during the Alfred E. Smith Memorial Foundation Dinner, a charity gala organized by the Archdiocese of New York, at the Waldorf-Astoria hotel, Thursday, Oct. 17, 2013, in New York. (AP Photo/Jason DeCrow)